SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '874a80a671fce16ead41d0eeb012dcb3969188f392cacc9a2050f0b9b746ba51' 
  AND token = 'DICfxue4lW7OFXeBr6d4PLKFiE+GQ1KDxwO9US7mHOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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