SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98c0c9ee0ec216689cc4e4374860723bdde41db4153230503b2b61a8eaabfbac' 
  AND token = '2Rxjsu0808oQ6ZQRHMbnSVkopYS8vsBsX/Ea0munGw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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