SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '998b3334f62ddce63fdc932b66d2fe3b76493ebab7b06dbe5ffd3ccd48168df1' 
  AND token = '0BOx+lXYfMkV1RlfJx/Ej4foiweRlgBBNe4RkbuCsAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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