SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e62194460bd9a8355aec6001be8b316dbfcacedcd2cf768ae53deff57068d45' 
  AND token = 'gu+YaCrWQnjL/VdZZfmVN8AtnIMAAG0trHU924uKFnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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