SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc5bd7a95671d0c3c83ee94fd38cfad94fb543c0fd0b536d28589f5ae293397' 
  AND token = 'MdHnuPl0RxIqjT5AnMhUAyvRUVY8Qzggs5+Bhc622i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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