SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0b3a4b5c9cbc2ed547a8593dac8d25d1310bc54ebd025dc4e6380a019096c604' 
  AND token = 'C+iUfa30p8Zlvgd3qwyD7kzc8ZbKEsnEHzNYGOEZ208=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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