SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38108f77d671eb9f6948c596ad9420257f27d56dd74e43f6621ab06d64cc28bc' 
  AND token = 'mu0cxugvoQiw6NFqoHLjig0/00aQAEVXyLmDYnMZPCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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