SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52e10ab8084a200b6845f9796386f542e6c7d2ba25526577bf5910c3c3a72a4' 
  AND token = '90w8y1tNfwAHKYUMqngzPot0mzs8fzBgrqhmWxlYYRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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