SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888cc81545339071e227c8c1f4009fc9500acef5f634e72095a532939cdb1cc0' 
  AND token = 'xP3wL8BlshHTo7fHerh0qMJXYT3rgoxmjiqHcVECHm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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