SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6962cdf26bb4c80b02ed0a8d033a814af96de8e9ec74e79470fb3a35c6cfad23' 
  AND token = 'sFqqPZecXKLSedqMLQ0cpC6q8IDS5IhtL2aoaRk06yU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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