SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16ebe5a1c38211a28216d9f0c113e1af8919da18a529192afbca47ae6d18c903' 
  AND token = 'fzvgPAPs8rKUVWnlcODbUCCXXChvMFlhH8rNoQwmqvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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