SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '868fc9a929f54c99cd2f91868dff0bd99edf796137fecb2bdd129abf9a756d7d' 
  AND token = '0uYiN3eLFVIG2fPgO7JeqwuKwoRwvdeZbAZYB5xjqdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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