SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98aa3d70a231c6bf6c25b46f03308ea5ba545bad1b17c647ffa394372404d889' 
  AND token = 'l3nH62UMwplmWGekvTRbRRjtDUZJZG2GcxNQDrRN7SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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