SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '112ebb9874dce5901fb22e65679477e5da38f52fb421de018200f93367c6abac' 
  AND token = 'Qjdmxyi44lSep84BmlaH6LqGW7McFhASK9Ooa7X15Os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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