SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c89a1b8b4367638b8c4192eae7a40ecca01fe540a561f130c628341ee314cc7a' 
  AND token = '/1gdpox/QoEMEQZwx8OhCvm+IJuYfBQzCiRpDayaCXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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