SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38ce567d0dc0e3ecff0bae1337d7d1a2078cff8f653847043e27e13795f89ea6' 
  AND token = 'SeFkO2PC6BZ9ICGQ+sXbTVYnPzCi6sRYrXinRwpjsTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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