SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4efc77e75b5b14f580b9e7cdcf8751c29a88fe93e1f31106f031b823dce35389' 
  AND token = 'IC1zOINWpMT2ez0PVgdRb62+L46262xvVmk0VNf6PoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}