SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590b02c35f7032cf765a70c9358a08f16d8e678acd9a29bc6a7e26cbe9d88a6f' 
  AND token = 'Cl5j+/qkgbAn68AG5fhzHLguThFNJ2IPFwKqWIqPuis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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