SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c494c8fb2cc882f16e1716cd28f847523b2b4f50d22dcc6979a7ddb97977f1f' 
  AND token = 'I9zvXDkHoVQXmyDYhEVMKqqYdQ0XNjSQQGAWR5Rcocw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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