SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '15ead456797b072a6191bb3e03139a74c81939679d27fea2f321a9698974af17' 
  AND token = '01plaxZH7n6u/TcA+aQp+YCKcLqixtwBMhWleH+ElNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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