SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0be704884eb887686868b9c7d786a23941a69ac299ef1e3b4c2fe02dff232cb5' 
  AND token = 'mqGHKMqruBavSUIC04agccJPm7rJ27aJkwoeoscmvRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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