SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c953daa4cd97d58cae8db5c239b13d417c577dbb970853b545dae1a5479ddd67' 
  AND token = 'vCmOfrFFLTLFiXyYmUT6OzIqktPZE2zVtySXE8CbMpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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