SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5126e46ba7b5dec3914bceb3c1f116b78b9a4b04dfc9e1a45cd333a1c627232d' 
  AND token = '6AGiIl+r99OXJ8hCcu8zn6Bg163ZjqrHuvOYhp8AwSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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