SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '011638c8c6e3000f64f75889f35fbb052e0792810364d836d9d623c8984ee630' 
  AND token = 'MMlNVwSoVbGfo1uKbtjZhjdI2YkyccFxvXre8omXbUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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