SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee52644f75d39c66b5b86c74f3093417869c789e7ec34137abfe818c022aa993' 
  AND token = 'IfIgBjt8gv1qgj5kLTPK7/xpSQ/pDiqdm+nUgBewj3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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