SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '775e89c4ad16bc9b06f2d766a5a4388fe34bbc937527d19b55836af945d05644' 
  AND token = '/WFeqVKacY5nrsLqhZp0CeUCf3ilU1qB1eVLn/20wtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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