SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206144466c265dc000095a0f96645c9c9169078abaebcc4dd128ea5c76d5ae09' 
  AND token = 'F1RsJpWKAHlFkgLbHtHbPHTJIAWai8rfuuoSbpQvLKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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