SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b14c6a2c0a96794f6815ce6efe543860d97106a66ab198172f333b52ea500603' 
  AND token = 'pZfkRcs8WYkIfAUBVv2418s9srhegnbm6fJu4nJLkMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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