SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54cbeaf8de02df7aae2bedc3c2586df7c6100c99b7e3a65532422187ef99c3d' 
  AND token = 'xQuzbgTKXc4vYlB6XVV8PKuWGl/mpXXJ+ONGkRyIkr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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