SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956a4ea534abac8fd26da723c48f4ee9e8aa9e333e991ff245627a410b17e531' 
  AND token = '8JT/P50nXgAYATLzhXM8lYjYiBpNgtfKUymN27dDWqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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