SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a0fc608a7f652b9425c8f0a857922e8826cd01778d013910ca032fd6d1574b1' 
  AND token = '7437lQcRHPqlvpgTvG/Zb6gKGQZHOleGWgbJ0YQj3VI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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