SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3e5df9160f99151128cb68c11e375551ff883e3a0ce817c68949a317a7804c4' 
  AND token = 'b0vzZA04jaEAJlUOADbtwQMccHKGAEXp2m1NjqTjGow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}