SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e700a3790f0031f1503485c9c3a7ad51e07e200f4da5e26709d33dfd8be29e' 
  AND token = '+Ns/nHRPjZ0kj0VHek4nSW589hPsFWvnF61buywu1nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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