SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5532f97b6f2f7dc80a49e53c94788a530be849d84d2b061d59f62de0fa34269f' 
  AND token = '9mKvWTz7ljCbBkgiMv0j7RMOAgFZxMn2uxfKEhomAsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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