SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3aa49c172c361644273e36645deefd5f2e2a6b18c2245f054516556e1ac9286' 
  AND token = 'u+VDgUFgniBS0boLh1p9ChxIxBs3NeYMcuk1VhjLApY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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