SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '253ea5f43aff47146c6e0651f33103528abad973bafc24e47b1bc5de61db02f9' 
  AND token = 'S3UnPYlRzVOoQuoPqRYanQCCRoVDTs791YArOmwj39k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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