SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df1f07cffd0a7efa6b70702387a1347718c1034621ba9b94e7f496035c50592a' 
  AND token = 'vED8/PwyVZoftWycE322nD8gzSeLEmfK2I71CmlM37Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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