SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da90029beabafd7424681576fe9b51dc3634993f0bbbc967aa4be28774af2085' 
  AND token = '4659VtAMNzLXns0N2tqI1TNZA5EA7TZ30QRqOL090IE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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