SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3bb1a35c09f4d0662434908303eb50093e6a5ac78d090ca644f1c9853bb02ddd' 
  AND token = '7TM1QrUXc72zhbC5E594mby6464LKD0WrHBNLieZ7Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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