SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '450c4eb31ffa63af2e013d305d8d7ab1d1d9f90877510f9e9a4730d7cfb71518' 
  AND token = 'l5eOYJ++H2SAcz+NsFJW3urhPbvxz5a9Ng6DEGSxrI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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