SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9587326283f8c52245f123b9ec52aff8c74c2d0bbdb7d6bac66daf4058a1ce76' 
  AND token = 'OS6jv+R9+dlDZhnuQupOs7/7xfZ6/zw7geTI3HYc6XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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