SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f731eaaab361d0823a95f4971e7d33c3af45e417b0181f7d43ed88e76f9d3b71' 
  AND token = 'kyaoXKRJFh0emltenX+WAUgqqRhwfHukPhoudikFsUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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