SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e8296ca0140d253387a52eda2791ee35674174f8df14c142559e7ce1ab7298' 
  AND token = '13wcycIKbP3r1qihJPGCmt7kESOlxiszIpkUYKAKvMc=' 
  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"
    }
  }
}