SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424339dc60a1db9a6f128e039b7d5a14b4c6fd5708189db40a0d97ffba577fd0' 
  AND token = '3yj0T29T/VKXz4/ee2CHL6kBuMEHsbGzr5HxBsFEpFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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