SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '760dcf42c980ad14d9df0145e84dbf990206128473980fe7d3361eecb743611e' 
  AND token = 'kibFgcGm+9suETMZrF1fSVgXkhotlB3aWzmmOVwIu/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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