SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e8e1fec95ad78bc403afc6193c835089c9907e61f6bd06bcbdc825548526884' 
  AND token = 'DOnTSJaQEhyDUFNPetoTtsuV6f+sb6QRqgU8Iod5g04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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