SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa0f4392eb2b919a0bdd1dfb6b51a24fd079c82b37787b4970b62af9d3bda81d' 
  AND token = 'v8iYVxBR5Fr+qTBhuKlHbZjp56UFlvBlQb4HcBeWJt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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