SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f6da615c8b3798564a22b338f13c4ae225c0387ba3b9d9a45b224b5dd1aa522' 
  AND token = 'FlynsPuZZZ4/aw4+HzC4Iax0j+SNYVSSpBqYV7yyaR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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