SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c7478657028d37cd2791c17cfa583d5f1f9daecae72e61718941ca3a267a36a' 
  AND token = '6r+X+7frpKBQq2ZXlccucTpYSh9AFTC6O0h7YWazjzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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