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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f70fa45b795709a9f3ef0808f54386e9e29a28bfe57ad248d585f0138fd84dc' 
  AND token = 'jQwFOJjoy+y8Ix0UrkEtLNPLmvmAf8jMR7Un11svj+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}