SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b2c97fc1586229b28a68f9fb0c2e4748550dd57c756504241f4381d545994f9' 
  AND token = '8eRJ/koJt19NBw8ttrJWZ0CNAe/Ot5Tlb0jH1c1iuqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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