SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e266e79ee7c54b5dcc659eb32f75223144b88b03795b1555e91a94c17c0f563' 
  AND token = 'MpshZL3vJvsj6DkGrINg1aL2mARuRgdsiTWgRFFKQDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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