SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f59ff6e967fdafd1bc4b554316d7419f208aad512ec5474a963ae09d50e0bac7' 
  AND token = 'SkIcrV3mci7cgMjx1yTLBSw2swOjZXqM7pbyb5huruE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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