SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb1d5f736850fb5ee737683d4a79ba50e20173f9781e08fd3928b6096a736fbb' 
  AND token = 'vKmS+ehy/cYwZtw7nrdYhRVZHYJPIdeZz3BYiqnxM0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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