SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf4e18b18ae925a923d1d71a8217281cda46573120c4078d1546630592973ce5' 
  AND token = 'esXCFfcWjlwDq0yU3lZ/+mzP19PKWufuPi1Lfkr3gKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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