SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f93dbe5b9f1c453aac256d3be6a0775de442f6389cccd32d1d10b25103e24b' 
  AND token = 'vHyZw2FqETB8xyupSRVqDVx7PIRkx4eyelpAEg3zKA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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