SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79f1048764d90c09547bef5af1afd8f922f4953405b4b15205af3a387bbb8199' 
  AND token = '/e8sS/Gb2h/5x3QdKTHPw1iehsyQWYtZtH27RhCs+Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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