SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '12c39f3cda473aa04b76faf959080df204012be1566cde39432e0fd7e1ac289f' 
  AND token = '+h5ytncduy9JVe3fZ4+SDTofyj0eCOa6fd7K6f0HdVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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