SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40cd055a54372c331819fe313d6fc434252e6c8cdfef2bb1ac65dcf173edf6c7' 
  AND token = 'DwqFGPjIs0bQgdmIaBWylcWVVs1N3LNwmCu+KDOgKMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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