SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f95b6e95c380edc961426ea406416133290c0e190238b4ea8ad29203c6d6a973' 
  AND token = 'qiYFuJH9j6ab3ZvZtSOpUiqrztlJSuJYTMTx8lmNFG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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