SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '197850d242c1e7bb1f3d69200ed5dc037c4195155a8d19c1f627c691027df889' 
  AND token = 'y80o6X38HysQHjajWRMGKxSKIYxiCyhVin92vZJH6lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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