SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6be40be0418714ab72e8dbcca778a2e5466e3e5e127b9b0883f4e952820d4b48' 
  AND token = 'vtUSE9fEWJVjg4hnGO/C5C2Qousl14T1n1O8pBh4IEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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