SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '697f816d394d334c9cd8dfb09a057e4b719931e1a45fb613fc61587934e64416' 
  AND token = '+NPWDyvs8py07NDY+vswP5zcDv52gkMphlUDhbc6urA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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