SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b94c84e914bcf4af4c26fec1aa98405782a05f7967b5aa67f30decc2d7fd405' 
  AND token = 'DUVQXhmSjuAoqlYX9g5WfUuNpctOlJpZLNGy7Y+Szq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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