SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db3414fbf31f023757b367bd9db0de48536eaaf952dfbbb34f25813b5bec2fa0' 
  AND token = 'hhweLyNsLkmb4eTRZV2pvWwGHLp5rRRJt4oobcMbrrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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