SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8341b7f2b8e319afee40c294603c702b85d3009c8a1113a4eec7169ad7516409' 
  AND token = 'HiCvXmzpCgI+ehxYzl0ow6N7fH9yMTm+AZ6TMvKxXLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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