SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebf475412e3726dcbe1f525923858722282e9fcf8a82ce8f23fcb5657637933a' 
  AND token = 'yQWqPG+OzMFiz1MmCw7y97K/IgVcg6cTwgAimyC/+uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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