SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbb0dc088de446f8c979e0db19c04b612af61f21c1a1a5958a94d098a6c25346' 
  AND token = 'TR7YQyjdf7+iZPFDSu2kfLaSROoetlMfSnM9GvoVl6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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