SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efeb25408e2cb4aa0621ac7fe1937ceb83047d43711d211f6bd052c023ffb446' 
  AND token = 'XIWGzf2nyJFTDNP1AjWSMp5Mg7w3TdHOLL87zubFwdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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