SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '29ea3ef7363f842a8467d23dac89aa21fb49d61133806d208b6f69ed7476d80b' 
  AND token = 'sUs5T1Ux4DOMjKTg7DW0pljhVq5vuiaFmLimkJ2AVwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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