SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2987fefd4cebebf929fbf582824fc9f55325f7b1833891151ec91dddd846df92' 
  AND token = 'NLpl3qfFZZhcdWlxGrnAptg4+3n3Q+1ZlxKq3HRrzHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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