SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '562923e185ae51136752a249af8eb37dc9653d284705f8503002a96523e6781a' 
  AND token = 'd4Z13XlsKnnBwXbNZkMqpvYW91To9VUUfuzTN+KSftQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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