SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbc16b8c18d65e50175d02cb759fa8cd2012631a36972175851d120f81e24952' 
  AND token = '85F5uxcx+W5CV+ra5UgI4VALUzbP9ycUl8m2FAUx4Zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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