SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6952488558c34ff51093403a7630e31a5dc5705301355ca9dd77db344ffbad12' 
  AND token = 'ZHSr2I2BGJwbgA8eISdYay4+8RKi5iVaEjDDk3gjhVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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