SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84597f34559f06dc57afb684ff22430354ed1be2b724c71e9239fa722398e8e4' 
  AND token = 'jDIG4aP9Syrh0ZBSXlCjN+3B2xkqAlRXSPfdW2GhpoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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