SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc420f00f752c9b26ddce4e6cd289c0ff7ab9482286b1ceaa800ce0ae3ffde6c' 
  AND token = 'TObpcdhE0S2ZNWi9wzlgfvcVSKQ47EhVbYEdNpto3ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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