SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21f877b2ff0ee1884181576c31fbf8cd59d35d761db4e0d3ba46880d553dd6cd' 
  AND token = 'Xw5G7ZWmG+b255ZnBb4fs7jVqZ4gFPJMPFTs22eevQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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