SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f94848841b9476e80b0fb7ae394471bfbe48d3176902273eb8c1d5129f0e21ff' 
  AND token = '9wnDqE4T7vXiXt5pMqbplbDZnp8GjFI67vwFKbKOXOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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