SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3560f35293465b43a8851bbffe14d7378623b8f12c57b8e2562d9ad352bbb408' 
  AND token = 'jqkQrzPW3/qKQZxanlmMpMq11faxfsXI2TTO0A7hc4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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